Search

Polysaccharides' derivatives are promising biologically active compounds for biotechnology, nutrition, industries, and are becoming increasingly important in medicine and pharmacy. Laminaran from brown alga Saccharina cichorioides (ScL) was chemically modified to obtain the carboxymethylated derivative (ScLCM) with improved structure and bioactivity. ScLCM was identified as (1 → 3)-β-D-glucan with -CH

Chitosan/fucoidan nanoparticles were created using two fucoidans from the Fucus evanescens algae. One of them was a regular fucoidan obtained for the first time from the alga harvested at the reproductive growth stage, using only standard extraction methods, without additional modifications. Its structure was established via NMR spectroscopy to consist of the repeating →3)-α-L-Fucp-(2,4SO3−)-(1 → 4)-α-L-Fucp-(2SO3−)-(1→ fragment. Such fragment also coustituted 55% of the other fucoidan's structure, however it also included long sequences of α-L-fucopyranose residues sulfated only at C2. The nanoparticles were re-dispersed in water and the influence of fucoidan/chitosan mass ratio on the nanoparticles' size and zeta potential was investigated. 3D models of the regular fucoidan and chitosan's sections were created and their molecular docking was performed, showing that either polymer could occupy the exterior of the complex, depending on their ratio. Thermodynamic parameters of fucoidan-chitosan binding process were accessed, with the results indicating that significant conformational changes of fucoidan and chitosan molecules take place during the interaction, presumably to allow for more effective binding.

Genomic analysis of the marine bacterium Wenyingzhuangia fucanilytica CZ1127T revealed the presence of four fucoidanase genes fwf1, fwf2, fwf3, fwf4 that belonged to the glycoside hydrolase family 107 (GH107, CAZy), which is located in one gene cluster putatively involved in fucoidan catabolism. Genes encoding two fucoidanases fwf1 and fwf2 were cloned, and the proteins FWf1 and FWf2 were produced in Escherichia coli cells. The recombinant fucoidanases were purified and the biochemical properties of these enzymes were studied. The amino acid sequences of FWf1 and FWf2 showed 41 and 51% identity respectively with a fucoidanase FcnA from the marine bacterium Mariniflexile fucanivorans, with the established 3D structure. Structures of the oligosaccharides produced during enzymatic hydrolysis of fucoidan by FWf1 and FWf2 have been determined by NMR spectroscopy. Detailed substrate specificities of FWf1 and FWf2 were studied using fucoidans and sulfated fucooligosaccharides with different structures. Both fucoidanases catalyzed hydrolysis of 1→4-glycosidic bonds between sulfated α-l-fucose residues but had different specificities regarding sulfation patterns of the fucose residues in fucoidan molecules. Specific cleavage sites recognizable by the fucoidanases in fucoidan molecules were determined. The obtained results provide new knowledge about differences between specificities of the fucoidanases belonging to the GH107 family.

Six fucoidan fractions were isolated from the brown alga Alaria angusta. Structures of enzymatic hydrolysis products of the fraction 1AaF2 (Fuc:Gal ~ 1:1; 33 % of sulfates) by fucanase from Wenyingzhuangia fucanilytica were studied by chemical and instrumental (NMR spectroscopy and mass-spectrometry) methods. It was shown that 1AaF2 consisted of two structurally different fucoidans: a sulfated 1,3;1,4-α-L-fucan and an enzyme-resistant sulfated and acetylated complex fucogalactan (Fuc:Gal ~ 1:2; 19 % of sulfates) 1AaF2_HMP containing extended 1,3-linked fucose and 1,3/1,4-linked galactose fragments (up to 5 residues). The fractions 1AaF2 and 1AaF2_HMP were a non-cytotoxic, possessed dose-dependent chemopreventive effect on EGF-induced neoplastic cell transformation of mouse normal epidermal JB6 Cl41 cells and inhibited the colony formation of human melanoma SK-MEL-28 cells.

In the present study, three sulfated polysaccharides, two fractions of fucosylated chondroitin sulfates, and one sulfated fucan were isolated from the body wall of the Vietnamese sea cucumber Stichopus variegatus. The structure of the sulfated fucan fraction SvF3 from S. variegatus was investigated for the first time. According to NMR spectroscopy data, the sulfated fucan SvF3 contained 1,2- and 1,3-linked α- l -fucopyranose residues. Sulfate groups were found at the 2 and/or 4 positions. The structural analysis of fucoidan was assisted by tandem mass spectrometry; the recently-developed technique of autohydrolysis in heavy‑oxygen water for the obtaining of selectively labeled fucoidan fragments was applied. The labeling (+2 Da mass shift at the reducing end) allowed us to assign MS/MS data unambiguously, and thus to confirm the NMR data and revealed minor sulfation at position 3. It was shown that the sulfated fucan SvF3 was not cytotoxic to human breast cancer T-47D and MDA-MB-231 cell lines, and it inhibited colony formation of those cells in vitro. SvF3 also possessed slight activity against migration of MDA-MB-231 cells in vitro.